Sponge Filters
PPI Comparison
4.25" Replacement for Hydro (sponge only)
6" Replacement for Hydro (sponge only)
Hydro Foam Replacement
Hydro Sponge Filter
Old-time Sponge Filter Style
Replacement Sponge for old-time filters
Old-time Sponge Filter Style
Old-time Spong Filter Lift Tube

Filter - Replacement Foam

Regular price $2.50
Shipping calculated at checkout.

Made from our Pro-Level Reticulated Foam, specifically suited for colonizing nitrifying bacteria at the highest levels in your aquarium.

As you can see from the list below, a 4.25" cube contains a lot more foam than a 4" one - over 20% more!

  • 3" cube filter has a volume of 27 cubic inches
  • 3.25" cube filter has a volume of 34 cubic inches
  • 4" cube filter has a volume of 64 cubic inches
  • 4.25" cube filter has a volume of 77 cubic inches
  • 5" cube filter has a volume of 125 cubic inches

The Filter - Replacement Foam destined to impress, and priced at only $2.50.

Inventory Last Updated: Sep 29, 2023

Customer Reviews

Based on 5 reviews
Jim Randall
Filter repair

Restored my filters perfectly

Carolyn Butler
Foam Filters!

These r a great product! We use these in all our 25 tanks and nothing else!
Maintenance is so simple, a few squeezes in some changed out tank water and ur good to go! Recommend them to anybody!

Jason Reiss
Great buy

Excellent product

Leslie Hall
Great replacement foam

I use these in my 200 gallon outdoor goldfish pond as a prefilter on my waterfall pump. They go much longer than the original hydro sponges before they need cleaning. Highly recommend.

Rich German
Replacement sponges

I’ve used these sponges for about 20 years and they are the best you can buy.They last at least that long because I’m still using a couple of them yet. I’m so glad they’re made to fit the API filters so I don’t have to buy a whole new replacement